changing static page metadata

I hope that someone can help…

For SEO purposes I’d like to add some additional text to the title (metadata) for each of the two static pages (already posted) in my blog – https://www.coppercoastworkshops.com/minimalistics/

I thought that I could just change the slug and the “Redirection” plugin would automatically take care of it, but not so, I just get a Page Not Found error. Many thanks… Seoirse